Electric circuit interrupter



May 15, 1934. D. s. RIVERS v ELECTRIC CIRCUIT INTEHRUPTER Filed March 30, 1933 //Y VE/YTOIT",

Patented May 15, .1934

UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to the art of electrical circuit interrupters and particularly to a device intended to break a circuit upon'overloads being applied thereto. Thedevice embodying my invention is intended to be used in the place of, the customary fuses having lengths of fusible wire and it is a primary object of my invention to provide a structure which may be reset for use again without having to replace fuse links or other fusible elements. A primary advantage of my invention is that it may be reset simply by rotating it and when reset will have exactly the same load rating as originally provided.

A further important object of the invention is,

to provide a structure which will have no mechanically moving parts and which may be made at an extremely low cost such that its use will be encouraged as a safety factor in protecting electrical circuits.

These and other objects and advantages will become apparent to those skilled in the. art by the following description of one particular form of structure embodying the invention as illustrated in the accompanying drawing, in which 3 Fig. 1 is a front end elevation of a structure embodying my invention;

Fig. 2, a side elevation; Fig. 3, a rear end elevation;

line 4-4 in Fig. 2; r Fig. 5, a vertical transverse section on the line 5,5 in Fig. 3;

Fig. 6, a vertical transverse section on the line 66 in Fig. 5, and 5 Fig. "I, a similar view to that shown in Fig. 6 but having the parts rotated slightly more than ninety degrees.

Like characters of reference indicate like parts throughout the several views in the drawing.

I form a base 10 out of any suitable insulating material which may be of a refractory nature such as glass or porcelain or may be of some synthetic compound, the essential characteristic of the material being that it is a suitable dielectric under ordinary operating conditions. Centrally through the base is passed a. rivet llhaving a head 12 exposed on the inner side and preferably countersunk within the base 10. The rivet extends through the base to protrude from the rear side and receive thereover a contactor 13. The end of the rivet 11 is headed over on this contactor 13 so as to retain it in a stationary position. Preferably the base 10 is slotted slightly to provide a groove within which the end of the con.-

tactor 13 fits so as to prevent rotation of the Fig. 4, a horizontal longitudinal section on the contactor about the rivet. This contactor 13 is bent around to have an end extend back over but in spaced relation with the end of the rivet as indicated in Figs. 2 and 5, and is of a spring-like nature so that it may be yieldingly pressed toward the head of the rivet.

A metallic ferrule or ring 14 is formed with threads rolled therein and is shaped with an inturned'annular flange at its rear end against which an annular projection extending from the base 10 may bear when the ring is slipped forwardly over the base. A cap 15 is formed out of some material similar to that employed in the base 10, preferably glass on account of its being molded easily, the essential characteristic of the material being that it be a non-conductor of electricity within the range of currents employed. This cap has an outer annular flange 16 and the rearwardly projecting portion is provided with screwthreads formed therearound adapted to enter internally within the threads formed in the ferrule 14 so that the cap 15 may be gripped by the flange 16 and screwthreadedly entered within the ferrule 14 and brought up against the forward face of the base 10 to form a tight joint 86 therebetween and force the base against the rear flange of the ferrule 14.

The interior of this cap 15 is formed in a peculiar manner to have a short groove 17 formed axially of the cap and to be open at the rear end 85. so that when the cap is brought against the base, the head 12 of the rivet 11 forms a closure across the rear end of the groove. A ribbon 18 of metal is formed to fit within a longitudinal groove cut across the threads on the outside of the cap to 90 bear against the inner side of the ferrule 14 and is carried downwardly through a slot across the rear end of the cap and thence forwardly within the cap and finally radially to enter within the groove 17 and flt across the front end thereof. The inside of the cap 15 is open above the groove 17 to form a chamber which is carried downwardly to a considerable distance below the groove. This chamber has an outer arcuate wall,

a flat wall 19 adjacent the groove parallel to the axis of the cap and an undulating wall or floor 20 extending across from the upper end of the flat wall 19 about the groove 1'7 and forwardly and upwardly to join by its outer side the circumferential wall of the chamber. The normal position of the cap is that indicated in Figs. 1-6 where the groove 1'7 is carried in a position so as to retain a fluid therein with the flat wall 19 extending downwardly near a side of the groove.

The floor 20 slopes upwardly and forwardly from the groove 17 and also upwardly and laterally therefrom so as to provide a directing gutter leading to the groove.

A quantity of mercury 21 slightly more than enough to fill the groove 1'7 is placed within the chamber defined in the cap. In use, the device assembled as above indicated is screwed within the ordinary fuse block (not shown) and by reason of the spring contactor 13, the device may .flange 16 and is revolved counterclockwise to carry the arrow around to points slightly below the horizontal wherein :the mercury 21 within the chamber in the cap will drop to' some such position as indicated in Fig. "I. Then the cap is rotaied back to bring the arrow to approximately the vertical position as indicated in Fig. 1 again, during which rotation, the mercury will flow down the floor 20 to be directed into the groove 17 and any excess of merc'ury'will flow on thereover and drop down into the chamber at the side thereof. The mercury then completely filling the groove 1'7 completes an electrical circuit between the end of the ribbon 18 extending within the groove and the head 12 of the rivet '11 so that the ferrule 14 and the contacior 13 are then interconnected electrically. Preferably the outer end of the ribbon 18 is soldered to the ferrule 14 'of mercury. The cross-sectional area of the groove 1'7 may of course be varied to determine the load carrying capacity of the device. Once the mercury is blown out of the'groove, the device may be reset to again establish the circuit by rotating the device first counterclockwise and then clockwise .to return the mercury to the groove .17. Thus it is to be seen that-I have. produced a very simple circuit interrupter which is entirely enclosed so that any arcing occurring on the breaking of the circuit is within the enclosing chamber within the cap 15 and explosion and fire hazard is eliminated. By. reason of the spring-like nature of the contactor 13, contact is retained within the fuse block during the slight rotation of the device while being reset. An advantage of the device isatonce noted in that any tendency of "it to'fail is in that direction wherein the load carrying capacity is reduced rather than increased.

' While I-have referred to the use of mercury as being the fluid-which is theaelement blown out of the groove 1'7, other current carrying fluids may be employedjn its place.

While I have here shown and described my device in the form as now best known to me, it is obvious that structural variations may be had without departing from the spirit of theinvention and I therefore .do not desire to be limited to this precise form beyond the limitations as may be imposed by the following claims.

I claim: 1. In combination, a base, an electrical conductor extending axially through the base to have terminals exposed on either end thereof,

a cap having an internal irregular shaped chamber defining in effect a horizontally disposedv minals at an end of the groove, a ferrule inter-- engaging the cap and base, a conductor connecting with the ferrule and extending to within said groove, and a quantity of a conducting fluid in the cap chamber.

2. In combination, a base, an electrical conductor extending axially through the base to have terminals exposed on either end thereof, a cap having an internalirregular shaped chamber defining in effect a horizontally disposed shelf with a groove therein, said cap being positioned against the base to have one of said terminals at an end of the groove, a ferrule inter-engaging the cap and base, a conductor connecting with the ferrule and extending to within said groove, and a quantity of a conducting fluid in the cap chamber, said chamber having a pocket adjacent said groove and having a wall extending up and around from the pocket to slope back down toward the groove whereby axial rotation of the cap will cause said fluid to flow around the wall into said groove.

3. In combination, a base, an electrical conductor extending axially through the base to have terminals exposed on either end thereof, a cap having an internal irregular shaped chamber defining in effect a horizontally disposed shelf with a groove therein, 'said cap being positioned against the base to have one of said terminals at an end of the groove, a ferrule interengaging the cap andbase, a conductor connecting with the ferrule and extending to within said groove, and a quantity of a conducting fluid in the cap chamber, said chamber having a pocket adjacent said groove and having a wall extending up and around from the pocket to slope back down toward the groove whereby axial rotation of the cap will cause said fluid to flow around the wall into said groove, the cross-sectional area of the groove being that to define a column of fluid said groove to said outer conducting member, said fluid when in said groove electrically interconnecting said first and second conductors.

DURWARD S. RIVERS. 

